3D打印用PA6/PA12复合粉末的制备与性能

采用溶剂沉淀法制备了用于3D打印的尼龙(PA)6/PA12复合粉末,使用扫描电子显微镜和X射线衍射对复合粉末微观形貌与结构进行分析,使用差示扫描量热测试了复合粉末的熔融和结晶温度,同时测试了不同PA12含量下复合粉末的表观密度、粒径分布、熔体流动速率(MFR)和注射成型件的力学性能。结果表明,复合粉末颗粒近球形,其结晶度明显低于纯PA6粉末的结晶度,当PA12的质量分数增加至20%时,复合粉末的结晶度由纯PA6的66.48%降至42.66%;随着PA12含量的增加,复合粉末的表观密度减小,粒径大于150μm的粉末含量增加,当PA12质量分数为20%时,复合粉末的表观密度仍大于0.35g/cm^3,粒径在75～100μm的粉末含量虽有所减少,但仍在70%以上,且加入成核剂可明显减少大粒径粉末的含量;MFR及注射成型件的韧性随PA12含量增加而提高,但成型件强度和模量下降;PA12使复合粉末的烧结温度有明显的降低,烧结温度窗口增大,有利于选择性激光烧结。

Preparation and Performance of Polyamide 6/Polyamide 12 Composite Powder for 3D Printing

The composite powder of polyamide(PA)6 and PA12 used for 3D printing was prepared by solvent deposition method.The morphology and structure of the composite powder were analyzed by SEM and XRD,the melting and crystallization temperature of the composite powder were measured by DSC,the apparent density,particle size distribution,melt flow rate(MFR)of the composite powder and mechanical properties of injection parts molded with the powder under different PA12 content were tested.The results show that,the powder particles were nearly spherical,and the crystallinity of composite powder was lower than that of pure PA6 powder.When the mass fraction of PA12 increases to 20%,the crystallinity of composite powder decreases from 66.48%to 42.66%.With the increase of PA12 content,the apparent density of the composite powder decreases,the proportion of powder with particle size larger than 150μm increases,when the mass fraction of PA12 is 20%,the apparent density is still higher than 0.35 g/cm3,although the proportion of powder with particle size 75–100μm reduces,it is still above 70%,and adding nucleating agent can reduce the proportion of powder with larger particle size obviously.The MFR of the powder and the toughness of the molding parts increase significantly with the increase of PA12 content,but the strength and modulus decrease.The sintering temperature of the composite powder decreases obviously and the sintering temperature window range increases with the addition of PA12,which is conducive to selective laser sintering.